Steering mechanism for portable hoists or excavators



` E. w. BARNHART 2,465,508 STEERING MECHANISM FOR PORTABLE HOISTS OREXCAVTORS 4. 2 Sheets-Sheet 1 March 29, 1949.

Filed 001'.. 15, 1945 un"llunullnnulll'w 74 lNvl-:N'ron EDGAR W.BARNHART ATTORNEY I March 29, 1949.

E. w. BARNHART STEERING MECHANISM FOR PORTABLE Filed oct. 15, 1945 vHoIsTs 0R ExcAvAToRs 2 SheetsfSheet 2 Z/ F162. 2z

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n EDGARW. BARNHART ,IW x\\\\l| ATTORNEY /0 *Venn Patented Mar. 29, 1949STEERING MECHANISM FOR PORTABLE HOISTS OR EXCAVATORS Edgar W. Barnhart,Marion, Ohio, assigner to The General Excavator Company, Marion, Ohio, a

corporation of Ohio Application Qctober 15, 1945, Serial No. 622,405

16 Claims.

This invention relates to portable self-propelled hoists and excavatorsand in its more spec'c aspects is directed to an improved steeringmechanism therefor.

One of the objects of the invention is to provide a steering mechanismfor a portable selfpropelled hoist or excavator which is interlockedwith the swing and travel mechanism of such devices.

Another object of the invention is to provide a steering mechanism for aself-propelled portable hoist or excavator having the power steeringunit therefor mounted on the swingable upper body or deck interlockedwith the swing and travel mechanisms to steer the hoist or excavator inany rotated position of the upper body relative to the chassissupporting same.

A further object of the invention is to provide a power operatedsteering mechanism for a portable self-propelled excavator or hoist inwhich a selectively operable hydraulic mechanism reversely operates ashaft for steering the hoist or excavator and in which the shaft isoperatively associated with the swing and travel mechanism.

Another and further object of the invention is to provide in a portableself-propelled excavator a reversely operable power steering mechanismoperated through a gear mechanism suitably associated with the operatingparts of the device to effect the steering action in any rotatedposition of the deck or upper body with respect to the chassis.

Another and further object of the invention is to provide a power ormotor operated steering mechanism having a portion pressure iiuidactuated and a portion mechanical and in which a part of the mechanicalportion is dif'posed in the journal connecting the deck and chassissupported frame, the control for said mechanism located at the operatorsstation.

Another and still further object of the invention is to provide apressure fluid steering mechanism for a pneumatically or solid tiredhoist or excavator chassis in which a portion of said mechanism isconcentrically disposed in the deck journal and shaft mechanism that ismechanically linked to the pair of wheels of said chassis employed insteering and controllable in any rotative position of said deck.

Other and further objects of the invention will occur to those skilledin the arts to which this invention relates as the description proceedswhich taken in connection with the accompanying drawings sets forth apreferred embodiment thereof, with selected modifications thereof but(Cl. 18o-79.2)

such disclosures are not to be construed as a limitation of theinvention which is limited only by the appended claims and any and allmodications, alterations and variations of structure coming within thespirit and scope thereof are deemed to be included herein.

In the drawings:

Fig. 1 shows a schematic perspective View partly in section of a hoistchassis steering control.

Fig. 2 is a perspective view of the swing and travel control connectionwith the steering mechanism.

Fig. 3 shows a side elevational view thereof.

Figs. 4 and 5 show schematic modified steering controls.

This is a continuation in part, of previous application S. N. 504,198,led September 28, 1943, entitled Steering mechanism for portable hoistsand excavators, which has been issued as U. S. Patent No. 2,417,963.

The advent of solid or pneumatically tired chassis for shovels, hoists,excavators, etc., has introduced the element of high traverse speed ofthe chassis over the ground and because of the fact that the device mustbe steered from the operators station on the rotatable deck the usualtype of motor truck and tractor steering devices are not employable, thelatter expedient not permitting any swinging motion of the steeringcontrol. The higher speed chassis has necessitated the adoption of atransmission unit comparable to that of a motor truck and theelimination of the dual clutch of the track laying traction unit orcaterpillar tread. It is necessary that the operator steer the excavatoror Vhoist from his station and with the pivoted front wheelscharacteristic of the motor truck and requiring great force to pivot thewheels some form of power unit is necessary that will be flexible andcapable of transmitting power through the deck journal and thenceapplying it to the forward wheels for steering the chassis. Furthermore,the weight of these machines is such that hand steering is dimcult andin some cases very nearly impossible. The operator in view of beingrequired to attend to a number of other controls cannot give undividedattention to steering so must have something that will respond quicklyand positively. This has been provided in the device disclosed in theaccompanying drawings which is not only simple to operate but isdefinite and certain in its action, economical to manufacture,functioning in any rotatable position of the deck relative to thechassis, easy to maintain and which transvmits power from the upper sideof the deck lt0 the front wheel twisting mechanism below the deckassociated with the chassis with no interference with the rotativemovement of the deck on its journal.

The above objects and advantages are obtained in the preferredembodiment of the invention set forth inFigs. l, 2.and 3 of thedrawings. A chassis frame l is supported cn rear drive wheels 2 and 3rotatably mounted on conventional axles (not shown) received in anautomotive type dif` ferential housing 4. The forward end of chassisframe I is supported on axle on whichswheels 6 and 1 are rotatablymounted on pivoted steering knuckle pin assemblies, one ofwhichisindicated by numeral 8 and the other is'not shown. The f twisting ofthe wheels in unison is accomplished by cross member 9. A suitable bellvcrank (not shown) but illustrated in the application referred to aboveillustrates how motion originating `in the rotatable body is.transmitted to the cross member 9 from the rod I9.

An upper body support II schematicallyillustrated is adapted tobe'supported on the chassis frame I. Support II is pro-vided with a boss`I2 the outer face of which is intended to function as a bearing surfaceon which the .platform or deck I3 of the rotatable upper body ismounted. The term deck as employed in this description is intended to besynonymous with rand the full equivalent of the term upper body as it isemployed in the portable self-propeller excavator or hoist art. Deck i3is bossed at i4 to tlboss I2 and may be equipped with bearingscustomarily provided at this point which enables the deck I3 to freelyrotate or swing relative to the chassis frame I and support II.

Disposed within the journal formed by bosses I2 and kI4 is a hollow ortubular shaft l5 rotatably supported in the journal in suitablebearings. Secured to one end of the shaft I5 is travel gear I6 whichrests on and is rotatably supported ona bearing surface provided onthe'deck 13. Secured on the other end of tubular shaft |5is a gear 'I1which in practiceis operatively connected through a suitable torque.tube drive shaft and gearing (not shown) with the axle mechanism inhousing 4. This connection is vwell known in the art and further detailsthereof as well as other mechanism are disclosed in greater detail in"Bulletin Cir-4120 published by TheGeneral EX- cavator Company ofMarion, Ohio. Gear I6 receives power from a suitable primemovervcarriedon the deck or in the upper body of the port-l able hoistor excavator as will be subsequently set forth.

'y Figsi 2 and 3 schematically show a swing and travel transmissionwhich originates in a gear I8 driven directly by a suitable prime movermounted on-deck I3. This gear drives a gear I9 by means ofV a powertransmitting means 29 which in the instant illustration is a gear chainbelt. Gear I9`issecured to a shaft 20 on which are mounted two clutchmembers 2| and 22 which have gears 23 and 24 respectively associatedtherewith. 'A coun-tershaft 25 suitably mounted for rotation in theupper body has a bevel gear 26 mounted on one end thereof meshing withgears 23 and 24 and .has a gear 21 formed on the other end thereof.'Clutch and gear elements 2|, 23 and 22, 24 are a portion of aconventional reversing mechanism. By means of this device shaft 25 maybe reversely rotated.

Gear 21 meshes with a gear 23 concentrically disposedl about a risershaft 29that is suitably mounted in the .deck I3. Av swingycontrolclutch `elements of the swing mechanism for the upper .body and themechanism associated therewith.

Thetravel mechanism customarily arranged in parallel .with the swingmechanism comprises a gear cluster33.composed of gear elements 34 andmounted on ashaft 35, gear 34 meshing with gear Ii'fmounted on centershaft I5 and gear 35 naled on deck I3 and a clutch 31 is associated rwith shaft 35 and gear 34 to disconnect gear 34 from gear 35 in ordertocontrol the travel of the hoist or excavator chassis.

The steering mechanism originates in a reciprocating type'pressure fluidmotor 39,y mounted on deck I3, to which supply conduits 49 and 4I arevconnected and they are also connected to a manually operated reversingvalve 42 to control the motion of :motor 39.. A suitable pump 43prefferably driven from the engine or `other prime mover customarilyfound on the deck I3 of the hoist or excavator* and incorporatingsuitable controls exhausts pressure fluid into pressure reserve tank 44throughA conduit 45 and by means of conduit 45 pressure Vfluidisconducted to `reversing yvalve 42 to `be conducted to one or the otherend ofl motor -39 depending upon the direction of steering desired. Anexhaust conduit 41 conducts fluidvfrom valve 42 to the .intake side ofpump 43. Wherever air is used as a pressure fluid medium this particularconduit 41 may be eliminated.

The motor 39 has a piston rod 48 which at its one end` is `connected tothe pistonl (not shown) inmotor 39. Piston .rod 48is provided withV asplit socket 49 at .its outer .end comprising a member 50 secured invsome appropriate manner to the piston rod 48 `and complemental member5I removably secured to the member 59 by suit ablescrew elements. Thetwo members 53 `and 5I each have a substantially hemispherical cavitytherein which receives bally 52integral with rod 53. The piston rod 48moves substantially transversely of the rod 53 and the ball .and socketmembers 49 and 52 permit this movement with out damage to either member.

The" rod. 53v has Van .enlargement 54 which is bor'edto receive a'bearing member 55 on which gear- `cluster 56 Vcomprising gears 51 :and58'is mounted. The gear'cluster 56- and the bearing therein are mountedfor rotation onvand relative to rod 59 concentrically disposed withrespect to the `shaft I 5-and mounted for relative rotation therein invsuitable journals. Gear 58 meshes with a 'gear 50 which is mounted onone end..of a shaft. 6Iv that. is: arranged in .suitable journals'fnotshownl'mounted on the deck I3.

A gearBZ is fixed to'the'opposite rend of the shaft 6I land meshes with:a gear 63 secured to the shaft 29. This `rschematically illustratesthe'interconnection between :the swing transmission mechanism soarrangedfor reasons to be subsequently set forth.

A gear 54, provided lwithr an extended hub, is rotatably mounted on therod 53 and meshes with the-gear.' 51 of. cluster .56:and also mesheswith geari 51 secured'toxthe shafti59 by keying orlotherwiseappropriately securing same thereto. Gear 65 is rigidly secured to theshaft 59 by means of key 65' and holds the shaft in position relative tothe travel mechanism shaft I5 and associated gears. Suitable bearingsurfaces are provided on the gears I6 and 65 to allow relative rotation.Rod 59 extends suiiiciently below the shaft I 5 such that a crank 66secured thereto may be connected to steering rod I0. A suitable joint61, well known in the art, connects the crank 66 and rod I0.

Figs. 4 and 5 show modified structures and only as much of the modifiedstructure as is necessary to show the essential structure is disclosed.All other mechanism is identical with that of Figs. 1-3 and for the sakeof clarity is not illustrated in connection therewith.

The gears 51 and 65 bear the same relationship to shaft 59 in Fig. 5 asthey do in Figs. 1-3. The rod 68 on which gear 69 is mounted meshes withgears 51 and 69. Shaft 68 is mounted for rotation in a member 10 whichis mounted on shaft 59 between gears 51 and 65 and for relative rotationwith respect to the shaft 59. A crank 1I is fixed to the shaft 68 towhich the piston rod 12 of motor 13 is secured. Motor 13 may becontrolled by devices similar to those shown in Fig. 1. The shaft 68 maybe supported for rotation in an additional journal (not shown) carriedon deck I3. Motor 13 is mounted upon the deck I3 for movement therewith.A suitable joint or connection is provided between crank 1I and thepiston rod 12 such that rotative movement may be imparted to shaft 68whenever desired.

The disclosure of Fig. 5 as indicated from the reference numerals isidentical with that of Fig. 4 but the rod 59 is not concentric with thesha-ft I5. Gear 14 in this instance is concentric with shaft I5 and issuitably supported therein. The rod 59 has a gear 15 thereon whichmeshes with gear 14. A member 16 secured to gear 14 is connectable bymeans of a suitable joint to the steering rod I9.

Each of these disclosures has been shown schematically in order tobetter portray the mode of operation and to avoid confusion of theessential mechanism herein set forth with the conventional structure ofthe portable self-propelled hoist or excavator.

The operation of the above described device depends upon the relativerotation of the several gear mechanisms. When, for example, the swingmechanism is rotating, gear 64 will roll relative to the gear 65 whichis held stationary because of its direct connection to the front wheelsof the device and because the motor 39 is rigidly connected to the decki3. This being true the motor moves with the deck therefore about shaft59 as an axis and causes gear 64 to roll relatively to stationary gear65.

When it is necessary to twist or steer the front wheels and axle of thevehicle the upper body or deck I3 is held stationary. Motor 39 is thenactuated by shifting of its reversing valve in one direction or theother and its piston rod 48 will pivot Ithe shaft or rod 53 about 59 asan axis and in rotating rod 53 it'will carry gear 64 along with itthereby rotating gear 65 and rod 53 about shaft 59 as an axis. Gear 64under this condition will roll relative to gear 51 because gear 51 isstationary and therefore rod 53 will rotate about bearing 55. Reverselymoving piston rod 45 will reversely rotate shaft 59 for the same reasonas set forth above. The motion or action of motor 39 and rod 53 isstopped by the appropriate valve when all vehicle Wheels are inalignment.

One typical phase of operation for the device willbe assumed in whichthe swing mechanism is disengaged with the transmission associatedtherewith being held at rest by the friction of the parts comprising theswing mechanism. The travel mechanism is engaged and is the condition ofthe device when the excavator or hoist has to be steered.

Now assume that the travel mechanism is disengaged and the swingmechanism engaged. Assume further that the upper body or deck isswinging in such a direction that the shafts 29 and 53 will rotate inthe direction of the arrows thereabout, or clockwise when viewed fromabove. Since the machine will not be traveling there will be nonecessity for steering. Upon rotation of the upper body or deck in thedirection indicated above, gear 3l will turn as shown by the arrowmarked on it. Referring now to the steering mechanism, shaft 56 does notturn relative to the center shaft 59 having gear 65 secured thereto.When the upper body is rotated, rod or shaft 53 is rotated around theshaft 59 along with the deck in a horizontal plane. Gear 64 must roll ongear 65 in the direction indicated by the arrow thereon. Gear 64 nowturns gears 51 and 58 on the stationary shaft 59. This causes gear 69,shaft 6I, gears 62 and 63 and the shaft 29 to rotate in the directionshown thereby showing that the steering wheels 6 and 1 will not be movedin response to the swinging of the upper deck or body. The ratios of thevarious gears 64, 51, 58, 60, 62, 63, 3| and 32 are so chosen that therotation of the upper body or deck and the action of the motor 39 willbe synchronized so that the gearing will freely mesh for accomplishingthe desired positioning of the deck relative to the wheels 6 and 1whether by swinging the upper body or by operating the motor 39.

The action in Figs. 4 and 5 is identical except that gear 59corresponding to gear 64 is rotated directly by reason of crank actionrather than by relative bodily motion of the one gear with respect tothe other as in Fig. 1.

That which is regarded new, novel and useful and which is sought to beprotected by Letters Patent of the United States is as follows:

1. In a steering control; a wheeled chassis having a pivoted forwardwheel assembly thereon; a rod connected to said pivoted wheel assembly;a deck; a swing mechanism for said deck; means journaling said deck onsaid chassis; a hollow shaft within said journaling means; a secondshaft rotatable within said hollow shaft; a translating means connectingsaid rod and said second shaft; a first gear xed to said second shaft; asecond gear rotatably supported on said second shaft and operativelyconnected to the swing mechanism for said deck; a bar element pivoted onsaid second shaft; a pressure fluid motor secured to said deck; meansconnecting said motor and said bar; a third gear rotatably supported onsaid bar and engaging said rst and lsecond gears; said third gearrolling on said first gear while said deck swings; and when said bar ispivoted by said motor said bar rolls said third gear relative to saidsecond gear and rotates said first gear and the second shaft connectedthereto to thereby twist said forward wheel assembly.

2. In a steering control; a wheeled chassis including a pivoted forwardwheel assembly; a rod connected to said forward wheel assembly; a deck;a swing mechanism for said deck; means journaling said deck on saidchassis; a hollow shaft4 :concentrically#disposed rforrsaid :journalingmeans; va shaft rotatably*supported-in.said hollow shaft;r'motiontranslating means:connecting said shaft and 'said'ro'dy a `barelement" pivoted to said shaft; a reciprocating pressure `luidmotorsecurabie to said deck; a sphere jointfconnecting said bar and thelpistonf'rody of-Y said :"motor; a

rst gear means rotatably supported on said shaft and adapted to engagethe swing mechanismsfor said deck; a secc-ndzgear xed to saidnshaft;athird gear rotatablyxsupported Yon said bar` meshing with said'first andsecond gears;; and-said third gear adapted to roll relative itc Isaidfirst gear when said motor pivots said barito twist said iorward'wheels;and to. roll relative to said second gear when said .-deck' rotates fon:said

chassis.

3. In a steering mechanism for. a portable hoist or excavatom'av wheeledkchassis having a pivoted forward wheel assembly .for steering saidIchassis; a deck; a swing z mechanismA for said deck; a journal torotatably support' said Ideck on said chassis; a rod axially disposedVvin'A said journal; means connectingsaid rodtiandirsaid forward wheelassembly; armut-or fixed to and mounted on said deck; means tocontrolsaid motor to reversibly operate same; imeans connecting saidmotor and said rod which includes a gear mechanism; means to associatesaid-:gear mechanism with the vswingtransmission of, 'the hoist; theswing mechanism .holding said; gear mechanism when said motor operatesto; pivot said forward Wheels; and said last mentioned means operable inany rotative position of said deck relative to said chassiswhile saidldeck is at rest.

4. In a steering mechanism for a portable `hoist or excavator; a wheeledchassis having a pivoted forward Wheel assembly for steering saidchassis; a deck; means vto rotate said deck; a journal 'to rotatablysup-port said deck on-said chassis; a rod axially disposed in saidjournal; means connecting said rod and said forward Wheel assemby; amotor mounted on said'fdeckmeans connecting said motor and said rodwhichiincludes a gear device one side Aoi'vvhich is connected to thedeck rotating mechanism; means to control said motor; and said motoroperative in any rotative position of said deck' relative to saidchassis while said deck is at rest, said Adeck rotating .mechanismholding said one side of said gear device to Y.enable said'motor topivotsaid wheel assembly, .and said l'wheel assembly holding the other sideof said gear device 'when said deck is rotated.

5. In a steering apparatus for a portablehoist or excavator; awheeledchassis in which the forward Wheels are pivoted; a deck; ajournalassociating said deck and chassis to enable said deck to rotatewith respect to said 'chassis;,ra shaft axially disposedin said journal;rmeans connecting said shaft and said pivoted wheels;l a gear device onsaid shaft; means connecting the gear device and theswing .mechanism-forv said deck; one side of said gear -devicejsecured to said shaft;and means to rotate'saidonesideof said gear device with respect to theother side thereof to pivot said forward wheels to steer said chassisand said last mentioned means holding said forward wheels in adjustedposition when said'deck rotates, said lastmentioned means operable inany rotated position of. said deck relative :t said chassis while saidvdeckis at rest.

6. In a steering apparatus.;for ai portable hoist or excavator; achassis having a pivoted forward wheel assembly toy steer same; a" deck;means to rotatably mount', said deck :on said chassis-which includes ajournal; vva shaft" axially disposed in said journakmeans to vtransmitmotion from saidshaft to said Vpivoted forvvard=wheelas sembly; meanstorotate said shaft whichincludesaa gear--devicefand a motor; means toholdfone side ofl said'gear device' at rest while said-motor rotates theother ,side ofesaid device, said othervside connected tosaid shaft, andmeans to hold said other side at rest relative to'said motor when vsaiddeck rotates; and means to reversely operate said motor.

l'7. .In a steering apparatus fora-portable hoist orexcavator a chassishaving a vpivoted 4forwardy wheel assembly; a deck; journal means :torotatably mount said deck .on said chassis; a shaft transverselydisposed with respect to said ydeck; means to transmit 4motion'imposedon said shaft to `said 'forward wheel assembly; means-to lrotatesaid-.shaft whichincludes ay gear device one'part of ywhich'isrotatablerelative to said shaft and the other, part oiA which is xed tosaid shaft and meansr connecting said'parts; a reversible motorto'actuate sa'idpconnecting means mounted on said deck; said partrotatablewithrespect to said ishaft connectable to the deck rotatingmeans; andsaid motor and said; gear device so constructed yand arrangedas Yto-.be `operable, in any rotative position of said deckrelativeto'said chassis while said chassisfis at rest.

' 8. vIn a steering control, a chassis having a pivoted forward wheelassembly to vsteer same;;a deck journaled on'said chassis; aimotormounted on said deck; a shaft,disposedsubstantially: parallel to theaxis 4of rotation of said deck; a gear mechanism; swing mechanism forsaiddeck; means associating onesideof said gear mechanism and said swingmechanism; meanstooperatively` associate `the other sid-e of said gearmechanism with said pivoted wheel assembly; and means to associate saidgear mechanism and said motor;` said swing mechanism holding-'one side'ofA saidgear mechanism against rotation when saidv motor -is actuatedto pivot said for-l ward wheels; and said pivoted wheel assembly holdingthe other side of said gear mechanism when said swing mechanism swingssaid deck.

9. In a steering control, a chassis havingi a rpivoted wheelassemblythereon; a deck;` means f one of said gears and said swingtransmission;

means to operatively connect the second lof said gears and said pivotedWheel assembly; a motor on said deck; and means to operatively associatesaid motor and the third of said gears, said swing transmission holdingsaid gear devicewhen saidmotor -is actuatedl yto pivot said forwardWheels.

10. In--a steering control; a chassishavinga pivoted `forward wheelassemblythereon' to steer saidjfchassis; a, deck; means to journal lsaiddeck on'said chassis; a 'shaft in said means; gear meansv comprisingthreev associated gears associatedwith saidshaft, one of said gears xed'to said shaft and holding said shaft in said means; av swingtransmission for said deck; means connecting a second of said gears andsaid swing transmission; means connecting said shaft and said pivotedwheel assembly; and a reversible motor on said deck operativelyassociatedy with the third gear of-said gear device; said motor whenactuated causing said third gear to be rotated to thereby pivot saidwheel assembly while said swing transmission holds said second gearagainst rotation to enable the other two of said gears to rollrelatively to each other.

11. In a steering control, a chassis having a pivoted wheel assemblythereon; a deck; means to journal said deck on said chassis; a shaftconcentrically disposed in said means; a first gear Xed to said shaft; asecond gear rotatably mounted on said shaft; a third gear meshing withsaid first and second gears; a reversible motor on said deck; a rod onwhich said third gear is mounted, said rod movable about said shaft asan axis; a swing transmiss'on for said deck; means connecting said swingtransmission and said second gear; means connecting said shaft and saidpivoted wheel assembly; and means operatively connecting said motor andsaid rod, said motor when actuated rotating said first gear to pivotsaid wheel assembly and thereby steer said chassis while said secondgear is held against rotation by said swing transmission.

12. In a steering control, a chassis having a pivoted wheel assemblythereon; a deck; means to rotatably support said deck on said chassis; ashaft concentrically disposed in said means; a first gear fixed to saidshaft, said gear engaging said means to hold said shaft in position; asecnd gear rotatably supported on said shaft; a third gear engaging saidfirst and second gear; a rod pivotably mounted on said shaft, said thirdgear rotatably mounted on said rod; a reversible motor on said deck;means connecting said motor and said rod to rotate said rod about saidshaft as an axis; a swing transmission for said deck; means connectingsaid second gear and said swing transmission; and means connecting saidshaft and pivoted wheel assembly; said motor when actuated bodily movingsaid third gear about said shaft causing it to rotate said first gear tothereby pivot said wheel assembly, said second gear held againstrotation by said swing transmission.

13. In a steering control; a chassis having a pivoted wheel assemblythereon; a deck; means to journal said deck on said chassis; areversible pressure fluid motor on said deck; a first shaft in saidmeans; a first gear fixed to said shaft; a second gear rotatably mountedon said first shaft; a third gear engaging said first and second gear;means to rotatably support a second shaft at right angles to said firstshaft, said third gear secured to said second shaft; means connectingsaid second shaft and said motor to reversibly rotate said shafts; atransmission to swing said deck; means connecting said transmission andsaid second gear; and means connecting said first shaft and said pivotedwheel assembly; said motor when actuated rotating said third gear androtating said rst shaft while said second gear is held against rotationby said swing transmission.

14. In av steering control, a chassis having' a Wheel assembly withwhich to steer said chassis; a deck rotatably mounted on said chassis; afirst shaft carried on said deck; means to connect said first shaft withsaid forward wheel assembly; a rst gear fixed to said rst shaft; asecond gear rotatably mounted on said first shaft; a second shaftsupported on said first shaft for rotation about an axis at right anglesto the axis of rotation of said first shaft; a third gear fixed to saidsecond shaft and engaging said first and second gears; a transmission toswing said deck; means to connect said second gear and saidtransmission; and means to connect said motor and said second shaft torotate the latter to thereby rotate said rst shaft while said secondgear is held against rotation by said transmission.

15. In a steering mechanism for a portable hoist or excavator; a wheeledchassis having a pivoted forward Wheel assembly for steering saidchassis; a deck; means to journal said deck on said chassis; means torotate said deck on said chassis; a rod axially disposed in said journalmeans; means connectingsaid rod and said forward wheel assembly; a motormounted on said deck; means connecting said motor and said rod; whichincludes a gear mechanism one side of which is connected to deckrotating means and in which said deck rotating means prevents motion ina part of said gear mechanism to enable said motor when actuated topivot said wheel assembly; and means to control the direction ofmovement of said motor.

16. In a steering mechanism for a portable hoist or excavator; a chassishaving a pivoted forward wheel assembly to steer same; a deck journaledon said chassis; a reversibly operable motor mounted on said deck; ashaft disposed substantially parallel to the axis of rotation of saiddeck; a gear mechanism; a swing mechanism for said deck; meansassociating one side of said gear mechanism with said swing mechanism;means associating the other side of said gear mechanism with said shaft;and means associating said gear mechanism with said motor; said swingmechanism holding one side of said gear mechanism while said motoractuates the other side of said gear mechanism to thereby pivot saidforward wheels.

EDGAR W. BARNHART.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,100,080 King et al June 16,1914 1,393,119 Harris Oct. 11, 1921 1,518,808 Moore Dec. 9, 19241,845,161 Lewis Feb. 16, 1932

